drivers/base/dma-coherent.c:973:12: error: ?shrink_thread? defined but not used [-Werror=unused-function]

[Marietto2008]

I'm trying to compile your source code because I want to enable kvm,but :

root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# git clone https://github.com/OE4T/linux-tegra-4.9.git
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# cd linux-tegra-4.9/
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# git checkout oe4t-patches-l4t-r32.6
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# cp /proc/config.gz .
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# gunzip config.gz
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# mv config .config
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# make menuconfig (enable KVM)
root@marietto:/home/marietto/Desktop/jetson_nano_kvm/linux-tegra-4.9# make -j4

  HOSTCC  scripts/kconfig/conf.o
  HOSTLD  scripts/kconfig/conf
scripts/kconfig/conf  --silentoldconfig Kconfig
  CHK     include/config/kernel.release
  WRAP    arch/arm64/include/generated/asm/bugs.h
  WRAP    arch/arm64/include/generated/asm/clkdev.h
  WRAP    arch/arm64/include/generated/asm/cputime.h
  CHK     include/generated/uapi/linux/version.h
  WRAP    arch/arm64/include/generated/asm/delay.h
  WRAP    arch/arm64/include/generated/asm/div64.h
  UPD     include/generated/uapi/linux/version.h
  WRAP    arch/arm64/include/generated/asm/dma.h
  WRAP    arch/arm64/include/generated/asm/dma-contiguous.h
  WRAP    arch/arm64/include/generated/asm/early_ioremap.h
  WRAP    arch/arm64/include/generated/asm/emergency-restart.h
  WRAP    arch/arm64/include/generated/asm/errno.h
  WRAP    arch/arm64/include/generated/asm/hw_irq.h
  WRAP    arch/arm64/include/generated/asm/ioctl.h
  WRAP    arch/arm64/include/generated/asm/ioctls.h
  WRAP    arch/arm64/include/generated/asm/ipcbuf.h
  WRAP    arch/arm64/include/generated/asm/irq_regs.h
  WRAP    arch/arm64/include/generated/asm/kdebug.h
  WRAP    arch/arm64/include/generated/asm/kmap_types.h
  WRAP    arch/arm64/include/generated/asm/kvm_para.h
  WRAP    arch/arm64/include/generated/asm/local.h
  WRAP    arch/arm64/include/generated/asm/local64.h
  HOSTCC  scripts/basic/fixdep
  WRAP    arch/arm64/include/generated/asm/mcs_spinlock.h
  WRAP    arch/arm64/include/generated/asm/mm-arch-hooks.h
  WRAP    arch/arm64/include/generated/asm/mman.h
  WRAP    arch/arm64/include/generated/asm/msgbuf.h
  WRAP    arch/arm64/include/generated/asm/msi.h
  WRAP    arch/arm64/include/generated/asm/mutex.h
  WRAP    arch/arm64/include/generated/asm/poll.h
  WRAP    arch/arm64/include/generated/asm/preempt.h
  WRAP    arch/arm64/include/generated/asm/resource.h
  WRAP    arch/arm64/include/generated/asm/rwsem.h
  WRAP    arch/arm64/include/generated/asm/segment.h
  WRAP    arch/arm64/include/generated/asm/sembuf.h
  WRAP    arch/arm64/include/generated/asm/serial.h
  WRAP    arch/arm64/include/generated/asm/shmbuf.h
  WRAP    arch/arm64/include/generated/asm/simd.h
  WRAP    arch/arm64/include/generated/asm/sizes.h
  WRAP    arch/arm64/include/generated/asm/socket.h
  WRAP    arch/arm64/include/generated/asm/sockios.h
  WRAP    arch/arm64/include/generated/asm/swab.h
  WRAP    arch/arm64/include/generated/asm/switch_to.h
  WRAP    arch/arm64/include/generated/asm/termbits.h
  WRAP    arch/arm64/include/generated/asm/termios.h
  WRAP    arch/arm64/include/generated/asm/trace_clock.h
  WRAP    arch/arm64/include/generated/asm/types.h
  WRAP    arch/arm64/include/generated/asm/unaligned.h
  WRAP    arch/arm64/include/generated/asm/user.h
  WRAP    arch/arm64/include/generated/asm/vga.h
  WRAP    arch/arm64/include/generated/asm/xor.h
  WRAP    arch/arm64/include/generated/uapi/asm/kvm_para.h
  HOSTCC  scripts/kallsyms
  HOSTCC  scripts/dtc/dtc.o
  CC      scripts/mod/empty.o
  HOSTCC  scripts/mod/mk_elfconfig
  CC      scripts/mod/devicetable-offsets.s
  HOSTCC  scripts/dtc/flattree.o
  MKELF   scripts/mod/elfconfig.h
  CHK     scripts/mod/devicetable-offsets.h
  UPD     scripts/mod/devicetable-offsets.h
  HOSTCC  scripts/mod/sumversion.o
  HOSTCC  scripts/conmakehash
  HOSTCC  scripts/mod/modpost.o
  HOSTCC  scripts/sortextable
  HOSTCC  scripts/dtc/fstree.o
  HOSTCC  scripts/dtc/data.o
  HOSTCC  scripts/dtc/livetree.o
  HOSTCC  scripts/mod/file2alias.o
  HOSTCC  scripts/dtc/treesource.o
  HOSTCC  scripts/dtc/srcpos.o
  HOSTCC  scripts/dtc/checks.o
  HOSTCC  scripts/dtc/util.o
  HOSTLD  scripts/mod/modpost
  SHIPPED scripts/dtc/dtc-lexer.lex.c
  SHIPPED scripts/dtc/dtc-parser.tab.h
  SHIPPED scripts/dtc/dtc-parser.tab.c
  HOSTCC  scripts/dtc/dtc-lexer.lex.o
  HOSTCC  scripts/dtc/dtc-parser.tab.o
  HOSTLD  scripts/dtc/dtc
make[1]: Nothing to be done for 'dtbs'.
  UPD     include/config/kernel.release
  CHK     include/generated/utsrelease.h
  UPD     include/generated/utsrelease.h
  CHK     include/generated/timeconst.h
  CC      kernel/bounds.s
  UPD     include/generated/timeconst.h
  CHK     include/generated/bounds.h
  UPD     include/generated/bounds.h
  CC      arch/arm64/kernel/asm-offsets.s
  CHK     include/generated/asm-offsets.h
  UPD     include/generated/asm-offsets.h
  CALL    scripts/checksyscalls.sh
  LDS     arch/arm64/kernel/vdso/vdso.lds
  VDSOA   arch/arm64/kernel/vdso/gettimeofday.o
  VDSOA   arch/arm64/kernel/vdso/note.o
  VDSOA   arch/arm64/kernel/vdso/sigreturn.o
  VDSOL   arch/arm64/kernel/vdso/vdso.so.dbg
  VDSOSYM include/generated/vdso-offsets.h
  LD      usr/built-in.o
  CC      init/main.o
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      arch/arm64/mm/dma-mapping.o
  CC      init/do_mounts.o
  CC      arch/arm64/kernel/debug-monitors.o
  AS      arch/arm64/kernel/entry.o
  CC      arch/arm64/kernel/irq.o
  CC      arch/arm64/kernel/fpsimd.o
  AS      arch/arm64/kernel/entry-fpsimd.o
  CC      init/noinitramfs.o
  CC      arch/arm64/kernel/process.o
  CC      arch/arm64/mm/extable.o
  CC      arch/arm64/mm/fault.o
  CC      init/calibrate.o
  CC      init/init_task.o
  CC      arch/arm64/kernel/ptrace.o
  CC      arch/arm64/kernel/setup.o
  CC      arch/arm64/mm/init.o
  CC      init/version.o
  LD      init/mounts.o
  CC      arch/arm64/kernel/signal.o
  LD      init/built-in.o
  CC      arch/arm64/kernel/sys.o
  CC      arch/arm64/kvm/../../../virt/kvm/kvm_main.o
  AS      arch/arm64/mm/cache.o
  CC      arch/arm64/mm/copypage.o
  CC      arch/arm64/mm/flush.o
  CC      arch/arm64/mm/ioremap.o
  CC      arch/arm64/kernel/stacktrace.o
  CC      arch/arm64/kernel/time.o
  CC      arch/arm64/mm/mmap.o
  CC      arch/arm64/mm/pgd.o
  CC      arch/arm64/kernel/traps.o
  CC      arch/arm64/kernel/io.o
  CC      arch/arm64/mm/mmu.o
  CC      arch/arm64/kernel/vdso.o
  AS      arch/arm64/kernel/hyp-stub.o
  CC      arch/arm64/kernel/psci.o
  CC      arch/arm64/kernel/cpu_ops.o
  CC      arch/arm64/kernel/insn.o
  CC      arch/arm64/kvm/../../../virt/kvm/coalesced_mmio.o
  CC      arch/arm64/mm/context.o
  CC      arch/arm64/kvm/../../../virt/kvm/eventfd.o
  AS      arch/arm64/mm/proc.o
  CC      arch/arm64/kvm/../../../virt/kvm/vfio.o
  CC      arch/arm64/mm/pageattr.o
  CC      arch/arm64/kernel/return_address.o
  LD      arch/arm64/mm/built-in.o
  CC      arch/arm64/kernel/cpuinfo.o
  CC      kernel/fork.o
  CC      arch/arm64/kernel/cpu_errata.o
  CC      arch/arm64/kvm/../../../arch/arm/kvm/arm.o
  CC      arch/arm64/kernel/cpufeature.o
  CC      arch/arm64/kernel/alternative.o
  CC      arch/arm64/kernel/cacheinfo.o
  CC      arch/arm64/kernel/smp.o
  CC      arch/arm64/kvm/../../../arch/arm/kvm/mmu.o
  CC      kernel/exec_domain.o
  CC      arch/arm64/kernel/smp_spin_table.o
  CC      arch/arm64/kernel/topology.o
  CC      kernel/panic.o
  AS      arch/arm64/kernel/smccc-call.o
  AS      arch/arm64/kernel/sleep.o
  LD      certs/built-in.o
  CC      mm/filemap.o
  CC      arch/arm64/kernel/suspend.o
  CC      kernel/cpu.o
  CC      arch/arm64/kvm/../../../arch/arm/kvm/mmio.o
  CC      arch/arm64/kernel/efi.o
  CC      arch/arm64/kvm/../../../arch/arm/kvm/psci.o
  AS      arch/arm64/kernel/efi-entry.o
  CC      arch/arm64/kernel/ssbd.o
  AS      arch/arm64/kernel/bpi.o
  CC      kernel/exit.o
  LD      arch/arm64/kernel/probes/built-in.o
  CC      arch/arm64/kvm/../../../arch/arm/kvm/perf.o
  OBJCOPY arch/arm64/kernel/vdso/vdso.so
  AS      arch/arm64/kernel/vdso/vdso.o
  LD      arch/arm64/kernel/vdso/built-in.o
  AS      arch/arm64/kernel/head.o
  LDS     arch/arm64/kernel/vmlinux.lds
  OBJCOPY arch/arm64/kernel/efi-entry.stub.o
  LD      arch/arm64/kernel/built-in.o
  CC      mm/mempool.o
  CC      arch/arm64/kvm/inject_fault.o
  CC      fs/open.o
  CC      arch/arm64/kvm/regmap.o
  CC      mm/oom_kill.o
  AS      arch/arm64/kvm/hyp.o
  CC      kernel/softirq.o
  AS      arch/arm64/kvm/hyp-init.o
  CC      arch/arm64/kvm/handle_exit.o
  CC      fs/read_write.o
  CC      mm/maccess.o
  CC      arch/arm64/kvm/guest.o
  CC      kernel/resource.o
  CC      mm/page_alloc.o
  CC      arch/arm64/kvm/debug.o
  CC      fs/file_table.o
  CC      kernel/sysctl.o
  CC      arch/arm64/kvm/reset.o
  CC      fs/super.o
  CC      arch/arm64/kvm/sys_regs.o
  CC      kernel/sysctl_binary.o
  CC      fs/char_dev.o
  CC      mm/page-writeback.o
  CC      arch/arm64/kvm/sys_regs_generic_v8.o
  CC      kernel/capability.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/aarch32.o
  CC      fs/stat.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic.o
  CC      kernel/ptrace.o
  CC      fs/exec.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-init.o
  CC      mm/readahead.o
  CC      kernel/user.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-irqfd.o
  CC      kernel/signal.o
  CC      fs/pipe.o
  CC      mm/swap.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-v2.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-v3.o
  CC      fs/namei.o
  CC      mm/truncate.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-mmio.o
  CC      mm/vmscan.o
  CC      kernel/sys.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-mmio-v2.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-mmio-v3.o
  CC      kernel/kmod.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-kvm-device.o
  CC      mm/shmem.o
  CC      kernel/workqueue.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/vgic/vgic-its.o
  CC      fs/fcntl.o
  CC      fs/ioctl.o
  CC      arch/arm64/kvm/../../../virt/kvm/irqchip.o
  CC      fs/readdir.o
  CC      mm/util.o
  CC      arch/arm64/kvm/../../../virt/kvm/arm/arch_timer.o
  CC      fs/select.o
  CC      mm/mmzone.o
  CC      arch/arm64/kvm/hyp/../../../../virt/kvm/arm/hyp/vgic-v2-sr.o
  CC      mm/vmstat.o
  CC      kernel/pid.o
  CC      arch/arm64/kvm/hyp/../../../../virt/kvm/arm/hyp/vgic-v3-sr.o
  CC      fs/dcache.o
  CC      kernel/task_work.o
  CC      arch/arm64/kvm/hyp/../../../../virt/kvm/arm/hyp/timer-sr.o
  CC      mm/backing-dev.o
  CC      kernel/extable.o
  CC      arch/arm64/kvm/hyp/sysreg-sr.o
  CC      kernel/params.o
  CC      mm/mm_init.o
  CC      arch/arm64/kvm/hyp/debug-sr.o
  CC      mm/mmu_context.o
  AS      arch/arm64/kvm/hyp/entry.o
  CC      kernel/kthread.o
  CC      arch/arm64/kvm/hyp/switch.o
  CC      mm/percpu.o
  CC      fs/inode.o
  AS      arch/arm64/kvm/hyp/fpsimd.o
  CC      arch/arm64/kvm/hyp/tlb.o
  CC      kernel/sys_ni.o
  CC      kernel/nsproxy.o
  AS      arch/arm64/kvm/hyp/hyp-entry.o
  CC      arch/arm64/kvm/hyp/s2-setup.o
  CC      mm/slab_common.o
  CC      fs/attr.o
  LD      arch/arm64/kvm/hyp/built-in.o
  LD      arch/arm64/kvm/kvm.o
  LD      arch/arm64/kvm/built-in.o
  CC      kernel/notifier.o
  CC      kernel/ksysfs.o
  LD      ipc/built-in.o
  CC      kernel/cred.o
  CC      fs/bad_inode.o
  CC      mm/compaction.o
  CC      mm/vmacache.o
  CC      fs/file.o
  CC      kernel/reboot.o
  CC      mm/interval_tree.o
  CC      mm/list_lru.o
  CC      kernel/async.o
  CC      mm/workingset.o
  CC      kernel/range.o
  CC      fs/filesystems.o
  CC      fs/namespace.o
  CC      kernel/smpboot.o
  CC      mm/debug.o
  CC      kernel/ucount.o
  CC      mm/gup.o
  CC      kernel/groups.o
  CC      mm/highmem.o
  CC      kernel/irq/irqdesc.o
  CC      kernel/irq/handle.o
  CC      kernel/irq/manage.o
  CC      mm/memory.o
  LD      kernel/livepatch/built-in.o
  CC      mm/mincore.o
  CC      fs/seq_file.o
  CC      kernel/locking/mutex.o
  CC      kernel/locking/semaphore.o
  CC      fs/xattr.o
  CC      kernel/irq/spurious.o
  CC      mm/mlock.o
  CC      kernel/irq/resend.o
  CC      kernel/locking/rwsem.o
  CC      fs/libfs.o
  CC      kernel/irq/chip.o
  CC      kernel/irq/dummychip.o
  CC      mm/mmap.o
  CC      kernel/locking/percpu-rwsem.o
  CC      fs/fs-writeback.o
  CC      kernel/locking/spinlock.o
  CC      kernel/irq/devres.o
  CC      fs/pnode.o
  CC      mm/mprotect.o
  CC      kernel/locking/osq_lock.o
  CC      kernel/irq/autoprobe.o
  CC      fs/splice.o
  CC      kernel/locking/rtmutex.o
  CC      mm/mremap.o
  CC      kernel/irq/irqdomain.o
  CC      kernel/locking/rwsem-xadd.o
  CC      mm/msync.o
  CC      kernel/irq/proc.o
  LD      kernel/locking/built-in.o
  CC      mm/rmap.o
  CC      fs/sync.o
  CC      mm/vmalloc.o
  CC      kernel/irq/cpuhotplug.o
  CC      fs/utimes.o
  CC      kernel/irq/pm.o
  CC      mm/pagewalk.o
  CC      fs/stack.o
  CC      kernel/irq/affinity.o
  CC      fs/fs_struct.o
  CC      fs/statfs.o
  LD      kernel/irq/built-in.o
  CC      fs/fs_pin.o
  CC      kernel/power/qos.o
  CC      mm/pgtable-generic.o
  CC      kernel/power/main.o
  CC      fs/nsfs.o
  CC      mm/process_vm_access.o
  CC      fs/buffer.o
  CC      kernel/power/console.o
  CC      fs/block_dev.o
  CC      mm/init-mm.o
  CC      kernel/power/process.o
  CC      mm/nobootmem.o
  CC      mm/fadvise.o
  CC      kernel/power/suspend.o
  CC      fs/direct-io.o
  CC      mm/madvise.o
  CC      kernel/power/wakeup_reason.o
  CC      fs/mpage.o
  LD      kernel/power/built-in.o
  CC      kernel/printk/printk.o
  CC      mm/memblock.o
  CC      kernel/printk/printk_safe.o
  CC      fs/proc_namespace.o
  CC      mm/page_io.o
  CC      fs/efivarfs/inode.o
  CC      fs/devpts/inode.o
  LD      kernel/printk/built-in.o
  CC      kernel/rcu/update.o
  CC      fs/efivarfs/file.o
  CC      mm/swap_state.o
  LD      fs/devpts/devpts.o
  LD      fs/devpts/built-in.o
  LD      fs/exofs/built-in.o
  CC      mm/swapfile.o
  CC      kernel/rcu/sync.o
  CC      fs/efivarfs/super.o
  CC      kernel/rcu/srcu.o
  CC      kernel/rcu/tree.o
  LD      fs/efivarfs/efivarfs.o
  LD      fs/efivarfs/built-in.o
  CC      fs/exportfs/expfs.o
  CC      fs/kernfs/mount.o
  LD      fs/exportfs/exportfs.o
  LD      fs/exportfs/built-in.o
  CC      fs/kernfs/inode.o
  CC      fs/kernfs/dir.o
  CC      fs/kernfs/file.o
  CC      mm/dmapool.o
  CC      fs/kernfs/symlink.o
  CC      mm/sparse.o
  CC      mm/sparse-vmemmap.o
  LD      fs/kernfs/built-in.o
  CC      fs/nls/nls_base.o
  LD      kernel/rcu/built-in.o
  CC      kernel/sched/core.o
  CC      kernel/sched/loadavg.o
  CC      mm/mmu_notifier.o
  LD      fs/nls/built-in.o
  CC      fs/notify/fsnotify.o
  CC      kernel/sched/clock.o
  CC      mm/slub.o
  CC      mm/migrate.o
  CC      fs/notify/notification.o
  CC      fs/notify/group.o
  CC      fs/notify/inode_mark.o
  CC      mm/early_ioremap.o
  CC      fs/notify/mark.o
  CC      fs/notify/vfsmount_mark.o
  CC      fs/notify/fdinfo.o
  CC      fs/notify/dnotify/dnotify.o
  LD      fs/notify/fanotify/built-in.o
  CC      fs/notify/inotify/inotify_fsnotify.o
  LD      fs/notify/dnotify/built-in.o
  CC      fs/notify/inotify/inotify_user.o
  LD      mm/built-in.o
  CC      security/commoncap.o
  CC      kernel/sched/cputime.o
  CC      kernel/sched/idle_task.o
  CC      kernel/sched/fair.o
  LD      fs/notify/inotify/built-in.o
  CC      kernel/sched/rt.o
  LD      fs/notify/built-in.o
  CC      fs/proc/task_mmu.o
  CC      security/min_addr.o
  LD      security/built-in.o
  LD      crypto/built-in.o
  CC      fs/proc/inode.o
  CC      fs/proc/root.o
  CC      kernel/sched/deadline.o
  CC      fs/proc/base.o
  CC      fs/proc/generic.o
  CC      kernel/sched/stop_task.o
  CC      fs/proc/array.o
  CC      kernel/sched/wait.o
  CC      fs/proc/fd.o
  CC      kernel/sched/swait.o
  CC      fs/proc/proc_tty.o
  CC      fs/proc/cmdline.o
  CC      fs/proc/consoles.o
  CC      kernel/sched/completion.o
  CC      fs/proc/cpuinfo.o
  CC      fs/proc/devices.o
  CC      fs/proc/interrupts.o
  CC      kernel/sched/idle.o
  CC      fs/proc/loadavg.o
  CC      kernel/sched/cpupri.o
  CC      kernel/sched/cpudeadline.o
  CC      fs/proc/meminfo.o
  CC      kernel/sched/energy.o
  CC      fs/proc/stat.o
  CC      fs/proc/uptime.o
  CC      fs/proc/version.o
  LD      kernel/sched/built-in.o
  CC      kernel/time/time.o
  CC      kernel/time/timer.o
  CC      fs/proc/softirqs.o
  CC      fs/proc/namespaces.o
  CC      fs/proc/self.o
  CC      kernel/time/hrtimer.o
  CC      fs/proc/thread_self.o
  CC      fs/proc/uid.o
  CC      kernel/time/itimer.o
  CC      fs/proc/proc_sysctl.o
  CC      fs/proc/kmsg.o
  CC      kernel/time/posix-timers.o
  CC      kernel/time/posix-cpu-timers.o
  CC      fs/proc/page.o
  CC      kernel/time/timekeeping.o
  LD      fs/proc/proc.o
  LD      fs/proc/built-in.o
  LD      fs/quota/built-in.o
  CC      fs/ramfs/inode.o
  CC      kernel/time/ntp.o
  CC      kernel/time/clocksource.o
  CC      fs/ramfs/file-mmu.o
  CC      kernel/time/jiffies.o
  CC      kernel/time/timer_list.o
  CC      kernel/time/timeconv.o
  LD      fs/ramfs/ramfs.o
  LD      fs/ramfs/built-in.o
  CC      fs/sysfs/file.o
  CC      fs/sysfs/dir.o
  CC      kernel/time/timecounter.o
  CC      kernel/time/posix-clock.o
  CC      kernel/time/alarmtimer.o
  CC      fs/sysfs/symlink.o
  CC      fs/sysfs/mount.o
  CC      fs/sysfs/group.o
  CC      kernel/time/clockevents.o
  CC      kernel/time/tick-common.o
  CC      kernel/time/tick-broadcast.o
  LD      fs/sysfs/built-in.o
  CC      fs/eventpoll.o
  CC      kernel/time/sched_clock.o
  CC      block/bio.o
  CC      block/elevator.o
  LD      kernel/time/built-in.o
  CC      kernel/freezer.o
  CC      kernel/futex.o
  CC      fs/anon_inodes.o
  CC      block/blk-core.o
  CC      fs/signalfd.o
  CC      block/blk-tag.o
  CC      fs/timerfd.o
  CC      fs/eventfd.o
  CC      kernel/smp.o
  CC      fs/aio.o
  CC      fs/locks.o
  CC      kernel/kallsyms.o
  CC      block/blk-sysfs.o
  CC      kernel/utsname.o
  CC      block/blk-flush.o
  CC      kernel/pid_namespace.o
  CC      fs/binfmt_script.o
  CC      block/blk-settings.o
  CC      kernel/stop_machine.o
  CC      fs/binfmt_elf.o
  CC      drivers/amba/bus.o
  CC      block/blk-ioc.o
  CC      kernel/utsname_sysctl.o
  LD      drivers/amba/built-in.o
  LD      drivers/auxdisplay/built-in.o
  CC      drivers/base/component.o
  CC      kernel/elfcore.o
  CC      block/blk-map.o
  CC      kernel/irq_work.o
  CC      drivers/base/core.o
  CC      fs/coredump.o
  CC      kernel/cpu_pm.o
  CC      block/blk-exec.o
  CC      kernel/membarrier.o
  CC      block/blk-merge.o
  CC      fs/drop_caches.o
  CC      kernel/memremap.o
  CC      fs/fhandle.o
  CC      drivers/base/bus.o
  LD      kernel/built-in.o
  LD      sound/built-in.o
  LD      firmware/built-in.o
  LD      net/built-in.o
  AS      arch/arm64/lib/bitops.o
  AS      arch/arm64/lib/clear_page.o
  AS      arch/arm64/lib/clear_user.o
  AS      arch/arm64/lib/copy_from_user.o
  AS      arch/arm64/lib/copy_in_user.o
  AS      arch/arm64/lib/copy_page.o
  AS      arch/arm64/lib/copy_to_user.o
  CC      arch/arm64/lib/delay.o
  CC      block/blk-softirq.o
  LD      fs/built-in.o
  CC      lib/lockref.o
  AS      arch/arm64/lib/memchr.o
  CC      drivers/base/dd.o
  AS      arch/arm64/lib/memcmp.o
  AS      arch/arm64/lib/memcpy.o
  AS      arch/arm64/lib/memmove.o
  AS      arch/arm64/lib/memset.o
  CC      lib/bcd.o
  CC      block/blk-timeout.o
  AS      arch/arm64/lib/strchr.o
  CC      lib/div64.o
  AS      arch/arm64/lib/strcmp.o
  AS      arch/arm64/lib/strlen.o
  CC      lib/sort.o
  AS      arch/arm64/lib/strncmp.o
  AS      arch/arm64/lib/strnlen.o
  CC      lib/parser.o
  AS      arch/arm64/lib/strrchr.o
  CC      drivers/base/syscore.o
  AR      arch/arm64/lib/lib.a
  EXPORTS arch/arm64/lib/lib-ksyms.o
  LD      arch/arm64/lib/built-in.o
  CC      block/blk-lib.o
  LD      virt/lib/built-in.o
  LD      virt/built-in.o
  CC      block/blk-mq.o
  CC      lib/halfmd4.o
  CC      lib/debug_locks.o
  CC      drivers/base/driver.o
  CC      lib/random32.o
  CC      lib/bust_spinlocks.o
  CC      drivers/base/class.o
  CC      block/blk-mq-tag.o
  CC      lib/kasprintf.o
  CC      lib/bitmap.o
  CC      drivers/base/platform.o
  CC      block/blk-mq-sysfs.o
  CC      block/blk-mq-cpumap.o
  CC      lib/scatterlist.o
  CC      drivers/base/cpu.o
  CC      block/ioctl.o
  CC      block/genhd.o
  CC      lib/gcd.o
  CC      drivers/base/firmware.o
  CC      lib/lcm.o
  CC      lib/list_sort.o
  CC      lib/uuid.o
  CC      drivers/base/init.o
  CC      block/scsi_ioctl.o
  CC      lib/flex_array.o
  CC      drivers/base/map.o
  CC      block/partition-generic.o
  CC      lib/iov_iter.o
  CC      drivers/base/devres.o
  CC      block/ioprio.o
  CC      drivers/base/attribute_container.o
  CC      block/badblocks.o
  CC      block/partitions/check.o
  CC      drivers/base/transport_class.o
  CC      drivers/base/topology.o
  CC      block/partitions/msdos.o
  CC      drivers/base/container.o
  CC      drivers/base/property.o
  CC      drivers/base/cacheinfo.o
  CC      lib/clz_ctz.o
  CC      lib/bsearch.o
  CC      block/partitions/efi.o
  CC      lib/find_bit.o
  CC      lib/llist.o
  CC      drivers/base/power/sysfs.o
  CC      lib/memweight.o
  CC      lib/kfifo.o
  CC      drivers/base/power/generic_ops.o
  LD      block/partitions/built-in.o
  CC      block/bounce.o
  CC      drivers/base/power/common.o
  CC      lib/percpu-refcount.o
  CC      drivers/base/power/qos.o
  CC      drivers/base/power/runtime.o
  CC      block/bsg.o
  CC      lib/percpu_ida.o
  CC      lib/rhashtable.o
  CC      lib/reciprocal_div.o
  CC      drivers/base/power/wakeirq.o
  CC      lib/once.o
  CC      lib/string_helpers.o
  CC      drivers/base/power/main.o
  CC      block/noop-iosched.o
  CC      block/deadline-iosched.o
  CC      lib/hexdump.o
  CC      lib/kstrtox.o
  CC      lib/pci_iomap.o
  CC      lib/iomap_copy.o
  CC      block/cfq-iosched.o
  CC      lib/devres.o
  CC      lib/hweight.o
  CC      drivers/base/power/wakeup.o
  CC      drivers/base/power/clock_ops.o
  CC      lib/bitrev.o
  CC      lib/rational.o
  HOSTCC  lib/gen_crc32table
  CC      drivers/base/dma-mapping.o
  CC      lib/genalloc.o
  LD      drivers/base/power/built-in.o
  CC      drivers/base/dma-coherent.o
  CC      drivers/base/firmware_class.o
  CC      lib/percpu_counter.o
drivers/base/dma-coherent.c:973:12: error: ?shrink_thread? defined but not used [-Werror=unused-function]
 static int shrink_thread(void *arg)
            ^~~~~~~~~~~~~
drivers/base/dma-coherent.c:280:12: error: ?declare_coherent_heap? defined but not used [-Werror=unused-function]
 static int declare_coherent_heap(struct device *dev, phys_addr_t base,
            ^~~~~~~~~~~~~~~~~~~~~
drivers/base/dma-coherent.c:96:13: error: ?dma_debugfs_init? defined but not used [-Werror=unused-function]
 static void dma_debugfs_init(struct device *dev, struct heap_info *heap)
             ^~~~~~~~~~~~~~~~
  CC      lib/swiotlb.o
cc1: all warnings being treated as errors
make[2]: *** [scripts/Makefile.build:336: drivers/base/dma-coherent.o] Error 1
make[2]: *** Waiting for unfinished jobs....
  CC      lib/iommu-helper.o
  LD      block/built-in.o
  CC      lib/iommu-common.o
  CC      lib/syscall.o
make[1]: *** [scripts/Makefile.build:649: drivers/base] Error 2
make: *** [Makefile:1121: drivers] Error 2
make: *** Waiting for unfinished jobs....
  CC      lib/checksum.o
  CC      lib/strncpy_from_user.o
  CC      lib/strnlen_user.o
  CC      lib/ucs2_string.o
  CC      lib/sbitmap.o
  CC      lib/argv_split.o
  CC      lib/bug.o
  CC      lib/chacha20.o
  CC      lib/cmdline.o
  CC      lib/cpumask.o
  CC      lib/ctype.o
  CC      lib/dec_and_lock.o
  CC      lib/decompress.o
  CC      lib/dma-noop.o
  CC      lib/dump_stack.o
  CC      lib/earlycpio.o
  CC      lib/extable.o
  CC      lib/fdt.o
  CC      lib/fdt_empty_tree.o
  CC      lib/fdt_ro.o
  CC      lib/fdt_rw.o
  CC      lib/fdt_strerror.o
  CC      lib/fdt_sw.o
  CC      lib/fdt_wip.o
  CC      lib/flex_proportions.o
  CC      lib/idr.o
  CC      lib/int_sqrt.o
  CC      lib/ioremap.o
  CC      lib/irq_regs.o
  CC      lib/is_single_threaded.o
  CC      lib/klist.o
  CC      lib/kobject.o
  CC      lib/kobject_uevent.o
  CC      lib/md5.o
  CC      lib/nmi_backtrace.o
  CC      lib/nodemask.o
  CC      lib/plist.o
  CC      lib/radix-tree.o
  CC      lib/ratelimit.o
  CC      lib/rbtree.o
  CC      lib/seq_buf.o
  CC      lib/sha1.o
  CC      lib/show_mem.o
  CC      lib/siphash.o
  CC      lib/string.o
  CC      lib/timerqueue.o
  CC      lib/vsprintf.o
  CC      lib/win_minmax.o
  GEN     lib/crc32table.h
  CC      lib/crc32.o
  AR      lib/lib.a
  EXPORTS lib/lib-ksyms.o
  LD      lib/built-in.o